Applicant's former U.S. Pat. No. 6,691,594 discloses a wrench wherein the pawls each have a protrusion on a top thereof and when installing the pawls into the recess defined in communication with the through hole in the head, the pawls have to be tilted such that the protrusions can be inserted in the recess first and then the two respective bodies of the pawls are rotated to be inserted in the recess. This spends too much assembly time. Some manufacturers break the portion between the through hole for receiving the engaging wheel and the recessed area for receiving the control member, such that the pawls can be inserted in the recess for the pawls directly without any angle adjustment. Nevertheless, the broken space weakens the structural strength of the head of the wrench.
U.S. Pat. Nos. 6,575,060 and 6,279,428 respectively disclose a wrench wherein the pawl includes a curve surface and the control member drives the center of the curve surface directly. As shown in FIG. 9 which discloses the structure of U.S. Pat. Nos. 6,282,991 and 6,282,992. The head 91 of the wrench 90 has a first hole 910 for receiving an engaging wheel 94 therein and a second hole 95 is defined between and in communication with the first hole 910 and a third hole 93 which receives a control member 92 therein. A pawl 96 is received in the second hole 95 and is engaged with the engaging wheel 94. a driving piece 97 has one end received int eh control member 92 and the other end of the driving piece 97 is engaged with a recess defined in the pawl 96. The pawl 96 is shifted left and right so that the distal end of the second hole 95 is in a broken state with the third hole 93, and the curve inside of the second hole 93 supports the pawl 96. The curve inside cannot provide sufficient support to the pawl 96.
The present invention intends to provide a wrench wherein a yield space is defined in an underside of the bridge portion located between the through hole for receiving the engaging wheel in the head and a recessed area for receiving the control member such that the protrusions of the pawls can be installed directly without any adjustment and the structural strength of the head of the wrench is reinforced.